Lack of any guidance in codes related to shallow (slim) floor constructions combined with a very limited number of tests in technical literature, gave us the spark to start our own experimental project related to DELTABEAM® Composite Beams against extreme situations, like earthquakes or column loss scenarios, to provide our customers with a safe, ductile, robust, and economical solution. The project consists of three parts: i) Bending behavior under positive moments (Sagging), ii) Bending behavior under negative moments (Hogging), and iii) Design and creation of a moment beam-to-column connection.
Design against extreme load cases demands ductile and flexible structural elements that must have adequate rotational capacity and be able to sustain huge deformations without losing their strength. To assess the flexural behavior of DELTABEAM®, 22 full-sized beams with various geometry and reinforcing details have been tested at the Institute of Steel Structures, National Technical University of Athens (NTUA), under both positive (sagging) and negative (hogging) bending loads.
The results showed that DELTABEAM®, in conjunction with proper steel reinforcement offers extremely ductile behavior. The test revealed that, in contrast with the commonly used composite beam cross-sections, properly reinforced DELTABEAM® can maintain its load bearing capacity even after the appearance of local buckling in the plates under compression, due to its ability to redistribute the stresses to alternative load paths in the cross-section. This beneficial structural response indicates that properly reinforced DELTABEAM® can be implemented by the designers not only for typical ultimate state designs but also for extreme cases, such as progressive collapse and earthquakes.
Additionally, the processing of the results will shed light to various aspects related to the design of DELTABEAM® against bending moments in extreme situations and will make our calculating methods more efficient. Design tools and technical documents will also be published after the completion of the project which now entered its third and last phase: The design and creation of a moment beam-to-column connection.
Read Peikko’s White Paper: Ductility Project – DELTABEAM® Slim Floor System
Simo Peltonen
M.Sc
Senior R&D Manager,
Peikko Group Corporation
Panagiotis Kyriakopoulos
M.Sc
R&D Engineer,
Peikko Group Corporation
